The term audio-visual aid refers to anything that an extension
agent uses to help to convey the message when communicating with
farmers. The spoken word is the agent's main communication tool,
but, whether the agent is speaking to a large village meeting or
discussing a problem in a field with a group of farmers, its
impact and effectiveness can be greatly increased by the use of
suitable audio-visual aids. When selected and used properly,
audio-visual aids can help in the following ways:

- The interest of the audience can be maintained if the agent
varies the mode of presentation. It is difficult to concentrate
for long on what someone is saying; but if the agent refers to a
wall chart, or illustrates a point with some slides, his
audience's attention can be maintained.
- When information is presented to more than one sense (sight and
touch, for example, as well as hearing), more is taken in and it
is better understood and remembered.
- Processes and concepts that are difficult to express in words
alone can be explained. The procedure for applying for a loan,
for example, may sound confusing, but a simple chart or diagram
can make the process clearer. Again, the life cycle of a crop
pest can be explained by showing a series of slides or drawings.
- The effects of decisions and actions that farmers might take
can be shown. Photographs of a cattle dip or a model of a
cooperative store can give farmers a clear idea of just what it
is they might be considering.
- Pictures can have a more immediate impact on our emotions than
words. Photographs of a heavy crop, for example, are likely to
arouse interest more effectively than details of yields read out
by an extension agent.

The range of audio-visual aids

Extension agents often use sophisticated audio-visual aids
which require electricity and complex machinery such as
projectors or television sets. But there are many simple aids
that the agent can make locally, and these have several
advantages. They do not require a power source or heavy
equipment, they do not cost much to produce and they can be made
to suit the precise needs of the agent. Between these two
extremes lies a wide range of more or less sophisticated aids.
The distinction between a mass medium and an audio-visual aid
lies only in the way it is used. All the mass media described
earlier can be used as audio-visual aids. A film is a mass
medium, in that it is shown to large audiences in many different
places; but for an individual extension agent who uses it to
increase the impact of a talk, it is an audio-visual aid. Many of
the principles of media use discussed earlier also apply to
audio-visual aids. The audio-visual aids available to the
extension agent can now be examined.

Objects

A real object is often the most effective aid. It enables the
audience to understand exactly what the extension agent is
talking about. Equipment and tools can be shown, samples of
diseased plants and insect pests displayed and different seed
varieties and fertilizers handled by farmers.

Where an object is too large to be shown, a model of it can
sometimes be used as a teaching aid. This applies particularly to
buildings and other fixed structures. The construction of a
poultry shed, for example, or the installation of a dip tank can
be demonstrated by using a model, which can be taken to pieces in
front of the audience.

Photographs offer another substitute for real objects. They
can be passed around an audience or displayed by the agent. If a
photograph is being taken to use as a visual aid, just the right
amount of detail should be included for the audience to recognize
it. Too much detail confuses and distracts, while too little
prevents recognition. Photographs of people doing things are more
likely to interest the audience than photographs of objects
alone.

Chalkboards

Blackboards are widely available in schools, rural training
institutes and extension offices. They may be fixed to an inside
wall or supported on a freestanding easel which can be moved
around. They are useful for setting down the main headings of a
talk, for sketching simple drawings and diagrams, and for noting
points raised in questions and discussion.

If using a blackboard, the agent should practice writing on
it, if necessary by drawing horizontal chalk lines for guidance.
He should make sure that the writing is large enough for someone
at the back of the audience to see clearly and that the headings
and phrases are kept short. There is not much space on
blackboards and the agent will lose the audience's attention if
he spends a lot of time with his back to them while writing.

Whiteboards have a smooth, shiny surface on which coloured
felt pens can be used, but it is important to use only pens with
water-soluble ink. Whiteboards are easier to use than blackboards
from both the agent's and the audience's point of view. The pens
flow smoothly over the surface and the colours are much clearer
than chalk on a blackboard.

Newsprint, which is an inexpensive paper, can be obtained in
large sheets and fixed to a blackboard or to the walls of a
building. It can be used in the same way as a blackboard but it
is more versatile. Text and drawings can be prepared on several
sheets, before a meeting, to avoid having to write while
speaking. Paper and pens can be given to small discussion groups
to note their conclusions. These conclusions can then be
displayed around the meeting-place and discussed by others.
Suggestions and ideas from the audience can be added to enable
farmers to see their decisions taking shape. Used sheets can be
kept for future reference. At a planning meeting with a group of
farmers, for example, the agent can take away the sheets to guide
him in preparing a written record of the decisions taken.

Posters

Posters are useful for highlighting the main theme of a talk
and wall charts can be used to show complex processes. Although
they are used mainly in class-room teaching where they can be
left on the wall for future reference, they can also be carried
by the extension agent to help him to convey ideas to farmers.

Flip charts

Flip charts contain a series of pictures, with or without
words, fastened along one edge between two sheets of thin wood or
thick cardboard. The two covers can be opened and folded back so
that the flip chart stands in front of the audience. Each picture
illustrates one point in the extension agent's talk and he simply
turns over each one when he moves on to the next point. As well
as helping the audience to understand and remember they remind
the agent of the structure of his talk without the need to refer
constantly to his written notes.

Many extension agents will already have access to printed
posters, wall charts and flip charts, but they can also be made
locally with large sheets of paper and coloured pens. When making
flip charts, the following points should be noted.

- Lettering should be large.
- Diagrams should be simple.
- Information on each sheet should be limited.
- Pictures from posters and magazines can be cut out and stuck on
by those who cannot draw.
- Pre-testing is important for all home-made visual aids.

Flannelgraphs

A flannelgraph is made from rough textured cloth, such as
flannel or a blanket, which is hung or supported almost
vertically. Figures, words, and symbols cut from cardboard, which
are backed with similar cloth or sandpaper, are attached to it. A
cheaper backing is obtained by putting glue on the back of the
cut-out and then dipping it into fine sand. The backing holds the
cut-outs firmly on the cloth surface. The cut-outs are prepared
beforehand and can be used repeatedly.

The flannelgraph can be used very effectively to build up a
story or an explanation. Unlike a wall chart, which can confuse
an audience by presenting a finished diagram at the start of a
talk, a flannelgraph can be used to present in turn each part of
the diagram until it is complete.

The cut-outs can be placed in different positions to show
alternative outcomes. After showing the process of wind erosion,
for example, the effect of wind-breaks can be demonstrated by
placing cut-outs of trees between the wind direction and a field.
Arrows representing the wind can then be deflected, and the
general effect shown by putting back soil symbols on the surface
of the field.

A modern alternative to flannelgraphs is the magnetic board.
Cutouts are backed by a magnetic strip, that holds them firmly to
a metal board. They can be used in windy conditions when
flannelgraph cut-outs would blow away, but they are cumbersome to
transport. On the other hand, flannelgraphs, which can be made in
a variety of sizes and designs can be folded into an agent's bag
or rolled up and tied to a bicycle.

Projected aids

Films, colour slides, filmstrips and overhead projector
transparencies are useful as teaching aids, bringing colour,
variety and interest to an extension talk. However, they all
require specific equipment and electricity. Extension agents are,
therefore, more likely to use them in training centres and
schools, although some slide projectors can be adapted to work
from a 12-volt car battery. Films, filmstrips and slides are best
used at night or in a room with curtains drawn or shutters
closed. Daylight screens can be used for small groups. Overhead
projectors can be used in daylight, provided the sun is not
shining directly on the screen or wall on which the image is
projected.

Colour slides can be selected and put in a suitable sequence
by the extension agent. He can produce his own slides to suit his
purposes, provided he has access to a camera, film and film
processing facilities. A slide set can easily be modified or
updated by replacing one or more slides. If they are kept dry and
free from dust and fingerprints, they will remain in good
condition for many years. An agent can either provide his own
spoken comments on the slides, or a commentary can be recorded on
an audio cassette. With synchronized equipment, the tape can be
modified so that slides automatically change at the appropriate
point.

Filmstrips contain a sequence of slides in a single continuous
strip of film. They are shown on a slide-projector fitted with a
filmstrip carrier between the projector body and the lens. They
cannot be modified easily and the sequence is fixed, but
individual frames cannot fall out or be put into the projector
the wrong way round. They are useful when a fixed message has to
be presented many times.

Overhead projectors are usually only found in class-rooms.
Diagrams and texts are put on to a sheet of transparent acetate
with special felt pens; the acetate is then placed on a flat
glass platform through which a light shines, projecting the
contents on to a vertical screen. The agent can write on the
acetate while facing his audience, or he can prepare it
beforehand. If he covers different parts of a sheet with paper,
he can gradually reveal the sections of a diagram, thus achieving
an effect similar to the flannelgraph.

Using audio-visual aids

Audio-visual aids are only effective if they are appropriate
to the situation and are used properly by the agent. Unsuitable
aids or ones that are not used properly can at best distract and
at worst mislead the audience. When selecting suitable
audio-visual aids, the agent will be limited to what is readily
available or can be made. Within that range, some aids are more
suited to a particular objective than others. For example, if
accurate detail is needed, a photograph, slides or a careful
drawing may be more appropriate. If, on the other hand, the agent
simply wants to highlight the structure of a talk or the main
conclusions of a discussion, a blackboard or newsprint will be
suitable. The agent should also consider where the aids will be
used: indoors or outdoors, with or without electricity, at a
large meeting or with a small group. All these factors will
influence the choice of audio-visual aids.

Proficiency in using audio-visual aids cannot be learned from
a book; it comes only with practice. The following principles
may, however, be useful, whatever audio-visual aids an extension
agent may use.

Select the aids most in accordance with your
objective, the composition and size of the audience where the
aids will be used.Use the aids to reinforce your message. They are
there for support, to complement and supplement the spoken word,
and should not be expected to communicate their contents without
explanation. Refer to them, explain them and ask questions about
them.Make sure that the audience will be able to see and
hear clearly. Audio cassettes that cannot be heard or lettering
that is too small to be seen can make the audience restless and
inattentive.Practise using the aids beforehand. Where projected
aids are used, it is important to be completely accustomed to the
equipment. For example, there are seven incorrect ways of loading
a slide into a projector but only one correct way.